This is what I was trying to explain in my post above.
I punch out these wax board cards from orange juice containers.
Then I ram the cards down onto the powder to highly compress it using a loading press.
After the balls are rammed, I experimented with putting cards over the balls, as a 2nd seal for the chambers.
But I stopped doing that due to being unnecessary.
However ramming the balls can additionally compress the powder.
This is what the cards look like after being fired through the barrel.
Using APP 3F, I've shot balls with and without lube and found that using lube is not necessary or recommended.
Once in a while I'll just swab out the barrel.
But I believe that compressing the powder greatly increases the velocity of the APP.